shotkey diode pros and cons, help !

I need to decide if a shotkey diode is needed for the aux battery on my electrically dependent ignition. It would isolate the battery from any demand in the battery or main bus system. It does drop the charging voltage a little. With B&C 410H alternator max charge amps should not be a problem. Dan H ( highly respected) has suggested ?a hot battery bus approach ?. Less is usually more, so what does a diode do for me in this scenario ?

Larry DeCamp said:

I need to decide if a shotkey diode is needed for the aux battery on my electrically dependent ignition. It would isolate the battery from any demand in the battery or main bus system. It does drop the charging voltage a little. With B&C 410H alternator max charge amps should not be a problem. Dan H ( highly respected) has suggested ?a hot battery bus approach ?. Less is usually more, so what does a diode do for me in this scenario ?

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The short answer - yes.

You want the aux battery to not discharge into whatever fault you had that forced you to rely on the aux battery to keep the engine running.

A lot of ways to keep an electrically dependent engine and/or panel up and running after a casualty somewhere in your power distribution system. Use of an aux battery is but one.

Carl

Here's one I recommend: Digikey V30100S-E3/4WGI-ND. It's current capability and forward voltage drop was selected to limit the maximum charging current to the backup battery. The details of this are beyond the scope of this discussion, but should be fine using any battery the same capacity or greater than the one I used, Digikey 522-1007-ND.

Here's an example of mounting one directly to a CB:



The Gozinas connect to the Master Bus, the Gozouta goes to the ignition breakers/backup battery bus.

V